I am using the following code to convert MAPI messages to MIME:
var mailMessage = msg.ToMailMessage(
ConvertAsTnef = false
var meoryStream = new MemoryStream();
PreserveSignedContent = true
var mime = meoryStream.ToArray();
If we have a MapiMessage that has an embedded message, the converted MIME has a problem when using Aspose.Email 18.1. The problem is that the message/rfc822 part has a bad Content-Transfer-Encoding. It has a value of base64.
According to https://www.w3.org/Protocols/rfc1341/7_3_Message.html, only “7bit”, “8bit”, or “binary” are allowed here.
This is causing problems when trying to parse the resulting MIME with some 3rd party library.
Please note that this problem does not exist in Aspose.Email 17.12.
The attached file has three files:
Message.msg: the input message
DoneWith17.12.eml: result of converting input message to MIME via Aspose.Email 17.12
DoneWith18.1.eml: result of converting input message to MIME via Aspose.Email 18.1
Messages.zip (13.9 KB)